AbbVie (NYSE:ABBV), which was spun out of health care stalwart Abbott Laboratories (NYSE:ABT) at the start of 2013, has beaten the market -- and its former parent company -- by leaps and bounds this year. It reported solid second-quarter results, largely fueled by 16% year-over-year sales growth of its top-selling autoimmune disease drug, Humira, but are there any threats to AbbVie's most important product? In the following video, from The Motley Fool's health-care show Market Checkup, analysts David Williamson and Max Macaluso review the highlights from AbbVie's second-quarter results, discuss the company's dependence on its high-flying blockbuster drug, and explain potential competitive threats to Humira, such as Pfizer's drug Xeljanz.

David Williamson owns shares of Pfizer. Max Macaluso, Ph.D. owns shares of Celgene. The Motley Fool recommends Celgene and Johnson & Johnson. The Motley Fool owns shares of Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.